Final answer:
The statement is false because in wrist flexion, the radius glides in a palmar direction, not dorsal. The movements of pronation and supination involve the radius rotating around the ulna, which can result in an X-shape position during pronation.
Step-by-step explanation:
The statement, "Open-chain wrist flexion results in a dorsal glide of the radius on the ulna," is FALSE.
Wrist flexion involves the movement of the wrist in such a way that the palm of the hand moves towards the anterior aspect of the forearm.
During wrist flexion, the distal end of the radius moves in a palmar or volar direction rather than a dorsal one. It is essential to differentiate between the various movements at the forearm to understand this concept correctly.
Pronation and supination are rotational movements where the radius and ulna can either be parallel (supination) or form an X-shape (pronation).
This rotational movement is due to the action at both the proximal and distal radioulnar joints. In the case of supination, the motion you use when scooping up soup with a spoon, the radius does not perform a dorsal glide.